About 20 Years of Silicon‐Based Thin‐Film Sensors with Chalcogenide Glass Materials for Heavy Metal Analysis: Technological Aspects of Fabrication and Miniaturization

Abstract

AbstractChalcogenide glass materials as membranes for potentiometric sensors for chemical analysis in solutions, e.g., ion‐selective electrodes, have been studied for more than three decades. Already in the 1970's, first papers dealt with the ion‐sensing properties of chalcogenide glasses, followed by systematic investigations of their solid‐state chemistry, the sensing mechanism and their analytical characteristics. Combining the analytical performance of chalcogenide glass membranes with techniques originally invented for semiconductor processing, a new generation of silicon‐based thin‐film sensors with chalcogenide glass materials for heavy metal detection has been created. In the beginning, co‐sputtering of Cu and As2Se3 resulted in a Cu2+‐selective field‐effect sensor, while in recent years, a variety of chalcogenide glass materials have been stoichiometrically deposited onto ISFETs (ion‐sensitive field‐effect transistor), EIS (electrolyte‐insulator‐semiconductor), LAPS (light‐addressable potentiometric sensor) and μISE structures, respectively, serving as miniaturized chemical sensors. The present review paper is devoted to research and development in the field of silicon‐based thin‐film sensors with chalcogenide glass materials and emphasizes technological aspects of fabrication and miniaturization within the last 20 years.